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Prepublished online as a Blood First Edition Paper on April 24, 2003; DOI 10.1182/blood-2002-12-3833.
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Blood, 15 August 2003, Vol. 102, No. 4, pp. 1333-1339
HEMOSTASIS, THROMBOSIS, AND VASCULAR BIOLOGY
The vitamin Kdependent -glutamyl carboxylase gene contains a TATA-less promoter with a novel upstream regulatory element
Elizabeth E. Romero,
Umaima Marvi,
Zachary E. Niman, and
David A. Roth
From the Center for Hemostasis and Thrombosis Research, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
The expression of the vitamin Kdependent -glutamyl carboxylase gene in liver is developmentally regulated. Since the gene product catalyzes an essential post-translational modification of the vitamin Kdependent blood coagulation proteins, the regulation of carboxylase expression is critical for hemostasis. We analyzed the activity of the rat carboxylase gene 5'-regulatory DNA sequences in rat hepatoma cell lines at different states of differentiation. These studies demonstrated that the 2.6-kb 5'-flanking sequence has differentiation-dependent transcriptional activity. Transient gene expression assays, examining the effects of nested deletions and site-directed mutagenesis of putative regulatory sequences, together with electrophoretic mobility shift assays (EMSAs) were used to identify sequences critical for the developmentally regulated transcription of the rat carboxylase gene. We identified a DNA sequence (76 to 65; GTTCCGGCCTTC) not known to bind to transcription factors, yet which functions as an upstream promoter element. In vivo genomic DNA footprinting confirms the presence of nuclear proteinDNA interactions at this site in the endogenous carboxylase gene in differentiated hepatoma cells. Therefore, this DNA sequence has specific nuclear proteinbinding activity and functional properties consistent with a regulatory element that plays a critical role in the developmental expression of the carboxylase gene, and hence the regulation of vitamin Kdependent blood coagulation protein synthesis.

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